The purpose of "Obesity Prevention in Latino Home and Community Environments" is to design, implement, and evaluate an environmentally-centered obesity prevention intervention for Latino children and their families targeting physical activity and dietary behaviors. The intervention will target not only the microenvironment in which the behaviors are likely to occur (i.e. the home environment), but also macro-environments (i.e., apartment complex, schools, grocery stores, parks, and restaurants.) The microenvironmental intervention will target structural aspects of the home and household rule setting delivered via community health workers (promotoras) and tailored to the needs of the family. The macroenvironmental intervention will employ promotoras to work in the environment (e.g., apartment complex, schools, and neighborhoods) to increase awareness and promote environmental change. The micro and macro environmental interventions, and their interaction, will be compared with a no-treatment control condition. The South San Diego County region where we will conduct our study has a population of 290,000, 60% of whom are Latinos. Primary study participants will be approximately 900 Latino children enrolled in grades K through 2 in public elementary schools. The child's primary care giver will also be recruited for concurrent participation in measurement and home- and community-based intervention activities. Twelve schools will be randomly selected to participate in the study, and randomly assigned to one of the four possible intervention conditions. The proposed study is a 2x2 factorial design, with neighborhoods (defined by primary school catchment areas) being randomly assigned to one of four conditions: microenvironmental intervention only ("micro"): macroenvironmental intervention only ("macro"), microenvironmental plus macroenvironmental intervention ("micro + macro"), or a no-treatment control condition. The study's primary outcome is Body Mass Index of the K-2 participants, measured at baseline, 12, 24, and 36 months. Secondary outcomes include observations and self report of nutritional, activity and sedentary behavior and related environmental characteristics. Moderator variables will include acculturation, socioeconomic status and GIS measures in the community.